This page provides release information about the SDK packages
available for download from the
SDK Manager,
in the SDK Platforms tab.

Each SDK Platform version includes the following packages:

The Android SDK Platform package. This is required to compile
your app for that version.

Several System Image packages. At least one of these is required
to run that version on the Android
Emulator.

Each platform version includes a system image for each supported form factor
(handsets, Android TV, and Android Wear). Each form factor may offer variations
to match your computor's processor architecture (such as Intel x86 and
ARM EABI). System images labeled Google APIs include access to
Google Play
services and those labeled Google Play also include
Google Play Store.

The Sources for Android package. This includes the source files
for the platform. Android Studio may show lines of code from these files
while you debug your app.

The revision numbers listed below are for the Android SDK Platform
package only. The system images may receive separate updates, usually to resolve
various bugs with the emulator. There are no release notes for the system images
but you should always keep them up to date.

Important: To see the most recent Android
system components in the Android SDK Manager, you must first update SDK Tools to the
most recent release and restart the SDK Manager.

Android 3.1 (API level 12)

Improvements to the platform's rendering library to support the visual layout editor in the ADT
Eclipse plugin. This revision allows for more drawing features in ADT and fixes several
bugs in the previous rendering library. It also unlocks several editor features that were added in
ADT 12.

Android 3.0 (API level 11)

Improvements to the platform's rendering library to support the visual layout editor in the ADT
Eclipse plugin. This revision allows for more drawing features in ADT and fixes several
bugs in the previous rendering library. It also unlocks several editor features that were added in
ADT 12.

Android 2.3.3 (API level 10)

Improvements to the platform's rendering library to support the visual layout editor in the ADT
Eclipse plugin. This revision allows for more drawing features in ADT and fixes several
bugs in the previous rendering library. It also unlocks several editor features that were added in
ADT 12.